Help! I am Losing fish constantly!

[Palmer92]

Hi all,

I have had my tank running for around 6 months and so far everything had been fine until the last 2/3 weeks. I am losing fish constantly recently but they show no sign of illness other than a slightly bloated stomach on the cardinal Tetras.

I am using a JBL test kit shich says no ammonia, Nitrite or Nitrate. PH IS 7.2 aswell.

Tanks is around 450 litres including the sump capacity with CO2 being piped into the inlet (Drop checker and test kit says it is safe). The tank gets a weekly water change with treated water about 25/30 percent. Currently stocked with 3 angel fish, 6 congo tetras, formely 10 cardinal tetras and 10 glowlight rasbora. Oh and about 20 cherry shrimp.

Nome of the fish look like they are fighting and when I get the bodies no one seems to have tried to eat them.

I am dosing all Seachem products as per the instructions on the back of the bottle 2 times per week for most items. The tank is heavily planted and I am at a loss as to what to do with it at the moment. I have tried an internal bacteria treatment but doesnt seem to have done anything.

So far I have lost about 5 cardinal, 4 rasboras and a congo tetra.

Any advice or help would be great.

 

[Kevin Eades]

Has there been any changes to the tank in that time? Have you added any new occupants which could have brought in disease or parasites?

The bloating would lead me to think disease or parasite as a first thought.

If there is nothing different with the tank then has something changed in the home?

New cleaning chemicals or air freshener etc which may cause contamination?

I had an issue once where someone used my bucket to clean with chemicals and I didnt know. I slowly contaminated my fish on water change.

When are the fish dying? overnight? Possible oxygen issues?. Are the fish active and eating normally?

These are the things that first come to my head if I was having the same issue. It might not be any of these I'm just saying what I'd question with my experience.

You mentioned you tested so unlikely ammonia spike.

side note I suggest you need to does more nutrients if nitrates are zero in a planted tank

 

[sparkyweasel]

As well as @Kevin Eades points above;
Are the fish breathing normally or fast?
Is your CO2 on a timer?
Does the CO2 level drop after lights-out?
Do you use aeration after lights-out?
If another one dies could you post pics of it?

A good idea when you can't pinpoint the cause of the problem is to do more frequent and/or bigger water changes.
If water quality is the cause it will obviously help, and if it's a disease it will help the fish to fight it.

 

[Palmer92]

Thank you all for your help.

CO2 is on a timer. No new air freshners etc.. I haven't added any new fish at the moment. No heavy breathing and I have treated for parasites. Drop checker goes blue about 2 hours after the co2 and lights go out.

Strangely enough after I posted I haven't had anyone dieing but will keep an eye out.

Thank you for your help and uf anything comes to mind please let me know.